Controllable propeller



July 7, 1936. P. F. HACKETHAL.

QONTROLLABLE PROPELLER Filed Aug. 1, 1934 3 Sheets-Sheet 1 y l lm P. F. HACKETH'AL CONTROLLABLE PROPELLER July 7, 1936.

Filed Aug. l, 1934 3 Sheets-Sheet 2 July 7, 1936 P. F. HAcaKETl-MLr 2,046,625

` A CONTROLLABLE PROPELLER Filed Aug. J.,l 1954 y A3 sheets-sheet :s

Patented July `7, 1936 Paul F.

Hackethal, Williamsport, Pa., assignor,

. by mesne assignments, to Aviation Manufacturing Corporation, Chicago, lll., a corporation of Delaware Application August l, 1934, Serial No. 737,870- 12 (Cl. 170-163) The invention irelates to adjustable propellers. j In aircraft propellers it is advantageous to adjust the propeller blades, usually by a variation of their pitch, to cause them to operate diierentially under different conditions, such as on the take-off, normal flying, and landing. In the type of controllable pitch propeller in which the pitch of the blades is effected by power and high ratio reduction gearing various forms of mechanical devicesshiftable by the pilot, have been used for engaging the'gearing when a pitch change is to be effected. Such devices included a system of rods,` bell-cranks or flexible shafts, which were influenced by deection in the aircraft structure upon which they are mounted. n Y

One object of the invention is'. to provide improved electromagnetically operated means for engaging the elements of the blade adjusting,

gearing; which will avoid the weight, cost and friction of the mechanical control andktlie disturbances in operation caused by deflections in the aircraft structure. This object is attained primarily bythe use of electromagnetic means for engaging the gearing to adjust the blades. By providing electromagnetic means for shifting the coupling and uncoupling member for this gearing to control the pitch changes, the weight, cost and `friction of and the resultant'vdeection in a mechanical control, such as a system of rods and bell-cranks or a iiexible shaft, are avoided.

, Another object of the invention is' to provide electromagnetically controlled means for adjust ingfthe propeller blades which can be easily installed and maintained.

Another object of the invention is to provide separate electromagnetic means for engaging and disengaging the gearing.

Other objects of the invention will appear fromV the detailed description.

' The invention consists in the several novel features and combinations hereinafter set forth and more particularly defined by claims at the conclusion hereof. In the drawings:

Fig. l is an axial section through a propellerembodying the invention.

Fig. 2 is a section taken on line 2-2 of Fig. l.

Fig. 3 is a diagram of the electrical connections and devices for controlling the form of the invention illustrated in Figs. 1 and 2.

Fig. 4 is a section on line 4-4- of Fig. 1.

Fig. 5 is a diagrammatic view of the gearing for varying the pitch of the propeller blades.

Fig. 6 is a view of the collar for engaging thel gearing to adjust the propeller blades.

Fig. 7 is a detail vof the internal shifting ring for the collar.

Fig. 8 is a transverse section of another form of the invention.

Fig. 9 is a section ou line 9 9 of Fig. 8.

Fig. 10 is a diagram of the electrical connections and devices for controlling the mechanism shown in Figs. 8 and 9.

The invention is illustrated, by way of example. as applied to aircraft comprising a propeller shaft I5, which may be the engine shaft, and journaled in the engine frame I6; a, propeller hub I1 xed to rotate with shaft l5; propeller blades I8 mounted in anti-friction bearings I 8, for rotation on their own axes and pitch adjustment in radial sleeves integral with the hub Il; and a worm gear 2| fixed to each propeller blade I8. The

mechanism for adjusting the blades is adapted to be driven by power derived from the rotation of the propeller shaft, and comprises a toothed gear 15 22 (Fig. 4), worm wheels 24 and 25 adapted to be driven by gear 22, a. worm gear 26 engaged by the worm 24. a shaft 21 ixed to gear 26, a worm 28 meshing with worm gear 2| on-one of the propeller blades, a gear 29 engaged by worm 25, a 20 shaft 30 fixed to gear 29, and a worm 3l on shaft 30 meshing with worm gear 2| on the other propeller blade I8. Worms 24 and 25 rotate the blades in opposite directions. Through this gear-` ing the speed reduction desirable for slowly and accurately adjusting the blades to the desired pitch is attained. All of this gearing normally is stationary in, rotates unitarily with the hub. and is uncoupled from the driving'means at gear 22. The means for operating the pitch change gearing in the hub is exemplied Iby a collar 32 pro vided with a right-hand screw or worm 33 engageable with the gear 22 to rotate the gearing in one direction to increase the pitchof the blades, and a left-hand worm 34 engageable with thegear 22 to drive the reduction gearing in the opposite direction todecrease the pitch. of the blades. Collar 32 is slidably and rotatably mounted in a sleeve 35 ixed to the front of the engine frame or casing I8. Pins 361, which are xed in sleeve 35,- extend through helical slots 31 in the collar 32. A ring 38 is internally mounted in collar 32, is rotatable therein, and is held against longitudinal .movement by pins 361 which extend into circumferential slots 39 in the ring. A shifter-arm or stud 40 is ixed to ring 38 and extends through a longitudinal slot 321 in collar 32. When arm 48 is shifted in one direction, it will rotate collar 32 and ring 38 and helical slots 3'Iv will move the collar longitudinally from its neutral position, and when the arm 40 is shifted in the opposite direction, the same means will shift the collar 32 longitudinally in the opposite direction. By this means the collar may be shifted from its neutral position to bring either of the Worms 33, 34 into mesh with gear 22 or back to neutral position.

Normally collar 32 ,is positioned so the. adjacent peripheral portion of gear 22 is between 32 is shifted forwardly,

gear 22 and rotate said gear to operate the gearing mounted in the hub to increase the pitch of both of the blades as the result ofthe rotation around the collar of the hub and gearing carried thereby. When the collar 32 is .shifted inwardly from its neutral position, worm 34 will engage gear 22 and drive the reduction gearing to decrease the pitchA of thev blades. This exemplies a device for engaging and driving the'power op-- erable gearing carriedv by the hub for adjusting the blades. e

In this form of the invention (Figs. l, 2 and 3) the electromagnetic means-for shifting the collar' 2`0 .41' which is mounted and xed lon sleeve 35, in

which the collar 32 is mounted; Casing 4I is fformed'of" sections meeting'in an axial plane'for 'convenience inl mounting and demounting the "control means for said collar contained therein 25 and bolts 42 secure the sections together.

f A rod 43 is slidably mounted in two-part casing 4| and the stud or 'arm -40 extends into 'a slot in 'said rod. Endwise movement of the rod will) rotateA ring 38. A lever, 44, fulcrumed 'atv 45 in casing 4|, has its lower end pivotally connected "at 8|, to one endof rod 43. The armature 46 of magnet 36 is connected by a link 41 to lever 44; lever 48, fulcrumed at 49 in'casing 4|, has

its :lower end pivotally connected. at 5|! to the other end of rod 43. The amature 5| of magnet 31 is'connected by a.link 52 to -lever 48. A spring 53, confined in housing 54, is applied to press 'afstem 55 inwardly. This stem has a shou'1d er 56-tolimi't its inward movement and a o slot 51 for a pin 58 on lever 44 which permits -said lever and rod143 to be independently shifted iby the magnet 31 and armature 5|. Spring 53 A"shifts lever-44 and rod 43 to neutral position when ,magnet 36 is deenergizedat the end of a i5. pitch-increasing operation. A spring 59 is ap- -Yp liedto lever 48 through a stem 6I! having a slot vand pin connection 6| with said lever to retract lever48and rod 43 to vneutral position whenmagnet 31l is deenergized at the end of a 550 'pitch-decreasing loperation. Stem 60 has a vshoui`cler'62 which engages the frame 4| to ar- -rest the stem when it has'shifted lever 48 to its 'neutral-position. The slot in the stem 60 permits the magnet '36 for shifting the collar 32 to pitch- "5a 'increasing position, to move the levers 44, 48 and rod4 43 vindependently of spring 59 from neutral "position to operative position. Y

, :The electrical connections for controlling Y magnets 36, 31 include a battery, or other suit- Y ablesource of potential 61, a switch 6 3 which isA `mounted within convenient reach of the pilot jandprovided with a contact arm 64 and contacts 65, 66 adapted to be engaged by said arm, and

relay switches 68 and 6,9 connected as indicated inFig. 3. v

The operation will be as follows: In normal ight', and while the blades are adjusted to the desired pitch, the collar 32 will be in its neutral position and disengaged from the gear 22. The 70 `connections between the electromagnets and the collar shifting arm 46 willthen be in the position 'shown in Fig. 2. The contact arm 64 will tirenv be disengaged' from both contacts 65, 66. "To

increase the pitch of -the blades, -the pilot-will A shift the contact arm 64 to engage contact 165,

, cluded. Armature 46 will then be shifted outwhich will establish a. circuit from battery 61 through arm 64, contact 65, the magnet of switch 68, and conductor 1|, andv close said switch.' This will establish a circuit from battery 61 through conductor 12- in which magnet 36 is inwardly to swing lever 44 and shift rod 43 in one "directiom .'I'he outer end of the collar shifter arm 46,.b eing connedin a slotin hub43, will be shifted in one direction to operate the collar 10 32 to cause worm 33 to engage gear 22. Blades I8 will be adjusted to increase their pitch by the gearing'between gear 22 and the blades. When theblades have been yadjusted to the desired degree,`the pilot will shift the contact arm .64 15 off contact l6,5. This will open the circuit for magnet 36 at switch 68 and deenergize said magnet. The spring 53 will then restore the lever 44,`rod 43, arm 46 and collar 32 to their neutral position, thus stopping the further increase of 20 the pitch'of the blades. To decreaselth'e pitch l of thefblades, thefpilot'will engage arm 64 and contact 66 to establish'a circuit from battery 61, -arm 64, contact 66, conductor 13 and the helix of relay switch 69. This will close a circuit from 25 battery 61 through conductor 14 in which the helix of magnet 31 is included, aridl the contacts of relay switch 61. Armature 5| will-then be shifted outwardly to swing lever 48 and shift rod 43 in one direction. This movement of rod 30 43 will shift arm 40 tov operate-the collar 32 to bring worm34 into engagement kwith gear 22.

Blades I8 will then be adjusted to decrease' their pitch by the gearing between'gear 22 and the blades. when the blades have been adjusted to 35' lthe desireddegree, the pilot will move contact arm 44 ofi contact 66 to open the circuit for mag'd net 31 at the relay switch 69 and deenergize said magnet. Spring 53 will then restore the -lever 44, rod, f43, arm 40 and collar 32^to their neutral po- 40 sition, thus stopping further `decrease of the pitch of the blades.

In the form of the invention illustrated in Figs,

1,8 and 9, the mechanism for shifting the collar 3 2 is operated by electromagnets to shift the col- 45 lar into neutral position, as well as operative position, thus dispensing with the retracting springs. This mechanism comprises a solenoid magnet for shifting the rcollar-32 into pitchincreasingposition, a solenoid` magnet 8| for 50 shifting said collar into pitch-decreasing position, a solenoid magnet 82 lfor shifting 'the collar from pitch-increasing to neutral position, and a solenoid magnet 83 for shifting theA collar from pitch-decreasing to neutral position. The hous- 55 ings of these magnets are xedly secured'by vbrackets 84 to the casing 85 which is mounted and fixed on the fixed sleeve 35,1in which the collar 32 is mounted, as previously described. This casingis formed in sections meeting in an axial 60 Aplane and secured by bolts for convenience in mounting and d ismounting, A pair of rods 86 and 81 areslidablymounted in the'casing 85 above and below the sleeve 35. Rod. 86 has 'a central socket\88, in which is conned the distal end of 65 the arm orv stud 40 which is xedly secured in ring 38, to operate collarv 32 aspreviously described. Rods 86 and 81 are connected at one side'of casing A85 to a lever 89 which is centrally fulcrumed at 90 in casing 85 and at the other 70 side to alever 8| which is centrally fulcrumed atA 92 in said casing. .Lever 89 is plvotally connected by a pin and slotconnection 93 with rod 81 vand by la pin and slot connection 94 with on'e end of the rod 86,'so that arm 40 will be shifted re- 75 sponsively to theA actuations of either of the magnets 80, 8| 'Ihe armature 95 of magnet 80 is connected by a link 96 to the lever 89 and the armature 91 of the magnet 8| is similarly connected by a link 91 to said lever These links are on opposite sides of the fulcrum 90, so that the attraction of the armatures 95,91 will operate lever 89and. rod 86 in opposite directions Lever 9| has one of its ends connected by a pin and slot connection 98 to one end of the rod 81 and its opposite end similarly connected at 99 to the rod 86. Above the fulcrum 92 armature |00 of magnet 83 is connected to lever 48 by a link |0| which has its inner end connected by a pin and slot |02. Below fulcrum 92 armature |03 is similarly connected by a link |04 and by a pin and slot connection |05 to lever 9|. c

Means for controlling the operation of the magnets 80, 8|, 82 and 83 comprises a switch |06 mounted within convenient reach of the pilot and provided with a contact arm I 01 and contacts |08,l |09, ||0 and.|||; a conductor ||2 connected to a. battery or other suitable source of potential ||3;and electric conductors as shown. These devices and connections exemplify means whereby the pilot may selectively cause the energizing of the electric magnets to control the movements .of the collar 32 by which the blades are adjusted.

The operation of the mechanism shown in Figs. 8 and 9 will be as follows: Normally the collar 32 will be in its neutral position and disengaged from the gear 22 and the electromagnetsl and the collar shifting arm 40 will be in the position shown in Fig. 8 and switch arm 06 will'open. 1

To increase the pitch of the blades, the pilot will shift contact arm |01 to engage contact |08, 'which will establish a circuit from battery ||3 through conducto-r ||2, arm 01,-contact |08 and magnet 80, to shift armature 95 outwardly and swing lever 89, and shift rod 8B and arm 40 in one direction. Arm 40 will shifty collar 32 into pitch-increasing position. When the blades have been adjusted the desired degree. the pilot will shift contact arm |01 oi contact |08 and onto contact |09. This will deenergize the magnet and establish a circuit to energize magnet 82. Armature |03 will be attracted and shift lever 9|, rod 86 and arm 40 to shift the collar 32 into neutral position and disengage it from the gear 22, thus stopping the further increase of the pitch of the blades. To decrease the pitch of the blades, the pilot will shift arm |01 onto contact I0 to establish a circuit from battery I3 through the helix of magnet 8|. 'I'his will attract armature 91 and shift lever 89,` rod 86, and arm 40 to move collar 32 from its neutral to its pitch-decreasing position by engaging worm 34 with gear 22. The pitch of the blades will be de creased through the operation of -gear 22 by worm 38. When the pitch of the blades has been decreased to th desired degree, the pilot will shift arm |01 olf contact ||0, which will deenergize magnet 91 and onto contact which will establish a circuit from battery ||3 to energize magnet 83. -Armature |00 of magnet 83 will be attracted and shift lever 9| to return rod 86, arm 40, and collar 32 i'nto neutral position. The lost motion permitted by the slots in links |0I, |04 allows the magnets 91, to move the collarshifting mechanism from neutral to pitch-changing'positions without shifting the armatures |00,

|03 of magnets 83, 82. A spring-detent ||5 is mounted in the fixed sleeve 35 to enter a bev- 4pilots cab and the controlling member which renders the gearing operative to adjust the blades.

While the invention has been illustrated and 1 described in connection with the construction of adjusting mechanism exhibited in patent to Smith No. 1,886,602, it is to be'understood that it is applicable to others.

The invention is not to be understood as limited 2 to the details set forth. since -these may be varied Within the scope of the appended claims, without departing from the spirit and scope of the invention.

Having thus described the invention, what I 2 claim as new and desire to secure by Letters Patent is:

1. In a controllable pitch propeller, the combination o f a shaft, a hub on the shaft, blades mounted in the hub for pitch changes, gearing 3 mounted in the hub for rotating the blades to vchange their pitch, a shiftable member around the shaft for engaging the gearing, electromagnetic means for shifting the member into different positions to engage and drive the gearing in 3 opposite directions, and electromagnetic means for disengaging said member. v

2. In a controllable pitch propeller, the combination of an engine casing, a, shaft, a hub on the shaft, blades adjustably mounted in the hub,` gearing mounted in the hub for 'adjusting the blades in opposite directions, a shiftable device for operating the gearing in opposite directions, and means for shifting said device comprising an electromagnet for shifting said device to drive the gearing in one direction, and an electromagnet for shifting the device to drive said mechanism in the opposite direction, said magnet being mounted between the hub and the casing.

3. In a. controllable pitch propeller, the combi- 5o nation of an engine casing, a shaft, a. hub on the shaft, blades adjustably mounted in the hub, gearing mounted in the hub for adjusting the blades in opposite directions, a device for operating the gearing in opposite directions, means for shifting said device, comprising an electromagnet for shifting said device to drive the gearing in one direction, and an electromagnet for shifting the device to drive said mechanism in the opposite direction, spring means for shift- 6 ing the device to its inoperative position, and a support for said shifting means supported by the casing inwardly of the hub andV on the outside of 4 and mounted on and carried by said fixed structure.

5. In a controllable pitch propeller, the comblnation of a shaft, a hub on the shaft, blades ro-` nation of a hub, blades rotatably mounted in the hub, gearing mounted in the hub for adjusting the blades, an annular member for engaging and operating said gearing,a fixed structure by which said annular member is supported, a pair of electromagnets disposedat opposite sides of said member .for shifting said annular' member to 'engage the gearing, and shiftingl means between the magnets and the annular member comprising a member movable longitudinally by the magnets and a pivotal connection between said members, said electromagnets and shifting means being supported by said xed structure.

'7. In a controllablepitch propeller, the combination of a hub on the shaft, blades adjustably mounted in the hub, mechanism.. mounted in the hub for adjusting the pitch of the blades, a shiftable device for engaging and driving said mechanism, and means for shifting said device in opposite directions comprising a pair of electromagnets and a pairfof pivoted levers operable by the magnets, respectively.

8. In a controllable pitch propeller, the combination of a hub on the-shaft, blades adjustably mounted in the hub, mechanism mounted in the hub for adjusting the pitch of the blades, a shiftable device for operating said mechanism, and means for shifting said device to operate said mechanism comprising a pair of electromagnets and a pair of pivoted levers, operable by the.' magnets, respectively, ,and a connecting rod between the levers.

9.v In a controllable pitch propeller, the combination of a hub on the shaft, blades adjustably mounted in the hub, mechanism mounted in the hub for adjusting the pitch of the blades, a device for operating said mechanism, shiftable into and out of engagementvwith said mechanism, a fixed structure adjacent the hub, and means mounted on the structure for shifting said device, comprising a pair of electromagnets, a pair of pivoted levers operable by the magnets, respectively, and a connection between said levers and said device. y

10. In a controllable pitch propeller, the combination of a hub on the shaft, blades adjustably mounted in the hub, mechanism mounted in the hub for adjusting the pitch'of the blades, a device around-the shaft for operating said mechanism, shiftable into and out of operative position, and means for shifting said device comprising a pair of electromagnets, a pair of pivoted levers, operable by the magnets, respectively, a rod con'- necting the levers, and an operating connection between the rod and said device.

11. In a controllable pitch propeller, the combination ofla hub on the shaft, blades adjustably l mounted in the hub, mechanism mounted in the hub for adjusting the pitch of the blades, a 'device for operating said mechanism, shiftable to engage the mechanism, means for shifting said device' comprising a' pair of levers and a pair of electromagnets for shifting said levers, respectively, for shifting the device to engage the gearing, and a pair of electromagnets for shifting the levers to shift the device tov disengage the gearing.

justably mounted in the hub, mechanism mounted a controllable pitch propeller, the combination of a shaft, a hub on the shaft, blades adin the hub for adjusting the pitch of the blades, a

shiftable device for operating said mechanism, means for shifting said device comprising a pair` of centrally pivoted levers, electromagnets for shifting said rods between the ends of the levers, re-

' spectively.

13. In controllable pitch propeller, the combination of a shaft, a hub ,on the shaft, blades adjustably mounted in the hub, mechanism mounted in .the hub for adjusting the pitch of the blades, a shiftable device for controlling and operating said mechanism, means for shifting said device comprising a pair of electromagnets, and a pair of levers operable by the magnets, respectively, and means havinga lost-motion connection with the levers for shifting the device into its inoperative position.

14. In a controllable pitch propeller, the combination of a hub on the shaft, blades adjustably` mounted in the hub, mechanism mounted im the hub for adjusting the pitch of the blades, a gear for operating said mechanism, shiftable into and out of operative position, means for shifting said gear comprising a. pair of electromagnets, a pair of levers operable by the magnets, respectively, for shifting the gearY into operative position, and

`electromagnets having lost-motion connections 16. In a controllable pitch propeller, the combination of a shaft, a fixed support, a hub on the shaft, variable pitch blades mounted in the hub, gearing mounted in the hub for rotating the blades to change'their pitch, comprising engageable and disengageable gears, a pair of electromagnets, means operable by the magnets for shifting said member, and a housing f or said means for supporting said electromagnts demountably secured on and extending around said support. y

417. In a controllable pitch propeller, the combination of a shaft, a fixed support, a hub on the shaft, variable pitch blades mounted in the hub, gearing mounted in the hub for rotating the blades to change their pitch, comprising engageable and disengageable gears, a pair of electromagnets, means operable by the magnets for` shifting said member, and a housing formed of sections for said means and supporting said electromagnets demountably secured on said support.

PAUL F. HACKEI'HAL. 

